Are axially symmetrical models of the dynamo adequate for modelling the geodynamo?

The question whether axially symmetrical models of the dynamo are suitable for generating the geomagnetic field is discussed. It is demonstrated that axial symmetry leads to the loss of the fundamental component of meridional flow, Archimedean wind. Hence, diffusion plays the main role in the equations of heat and light constituents transfer. The temperature and constituents distribution is then nearly axially symmetrical, and azimuthal flow and the omega-effect closely associated with it become small. This makes the generation by means of the alpha omega-dynamo impossible. A method of testing the asymptotic behaviour of numerical solutions for nu-->0 is also suggested. (C) 1999 Elsevier Science B.V. All rights reserved.